Wow looks great!!! I found a great tile site, I used to go to estate sales too but now I do most of my ordering online from Glasstiledecor.com - they are so cheap they have great brands, great prices and free shipping - hope this site works out as well for y'all as it does me - bc i am a mosaic nut! Here is a link that might be useful: glasstiledecor

I heard back from Schluter. Here's my question and their answer: Question: Can the uncoupling membrane be installed directly over existing ceramic tile? This is a basement - the tile is installed over the concrete subfloor. Tile is in good shape - just ugly. We don't want to remove it. So if the membrane can be installed over top, what type of thinset should we use to bond the membrane to the existing tile? Answer: If the following requirements are met, we expect this type of installation to be successful. However, given the wide range of potential existing conditions, this application is not covered by a specific detail in the Schluter-DITRA Installation Handbook and is therefore not covered under warranty. In principle, DITRA can be installed over existing tile. In general, the following minimum requirements must be met for a successful installation. The substructure must be adequate, per the DITRA Installation Handbook (e.g., joist spacing, plywood thickness, etc). The existing tile must be well bonded; any loose tile must be removed. The tile must be cleaned before the DITRA installation to remove any bond breakers. The DITRA can be installed in a similar fashion to what is called out in detail D-V-T in the DITRA Installation Handbook. (I looked this up, and it's referring to installing over vinyl.) Option 1. Use a rapid-setting modified thin-set mortar suitable for bonding to existing tile to install the DITRA Option 2. Skim coat the tile with a modified thin-set mortar or suitable cement-based embossing leveler, allow it to dry, and install the DITRA with unmodified thin-set mortar For further details please see attached Ditra installation Handbook

I believe the difference in color is too great with the white and brown. Why? 3 reasons 1. The products that are cemented to the building you will not redo anytime soon. Messy , dirty, expensive and just not worth the trouble  2. When you add a product to the building structure. Windows , floors they must last a long time. Durability, wear and tear, and STYLE. All equal a story of when the home was designed.  The look over a period of time 10 years + and the home will become "out of date" Needs a face lift . 3. The homes we admire, the Museums, Churches, Libraries, Opera House have one common thread. At a glance they are timeless. Built in 1940, 1990 etc  The crystal clear item is not seen  For this reason I would not go "trendy". Generally our first choice is the right one. Simple and elegant  How do you change this ad time moves on. Color Bedroom a change of bedspread. Bathroom towels become a dark navy or  deep forest green. Yellow for spring  Paint a wall blue, hang a piece of art  The change is simple and your money well spent for resale  Take a moment to do another board  Remove the brown and replace with a neutral. Try an Odegard runner - There are so many options  Enjoy

I did a google search on “terrazzo tile 1970” and found this blog entry. There seems to be a few sources outside of the norm HD or tile sites > https://suburbanpop.com/2021/02/22/where-to-buy-terrazzo-tile/